A £100,000 reward is being offered for the safe return of a solid gold toilet stolen from Blenheim Palace.
Detectives are still looking for the artwork, valued at $6m (£4.8m), which was stolen in a raid at the stately home in Oxfordshire on 14 September.
The palace's insurance company Fine Art Specie Adjusters (FASA) said up to £100,000 could be paid out as a reward.
Two men have been arrested on suspicion of burglary.
Philip Austin from FASA said: "The reward is up to £100,000 and terms are by approval of the insurance company, which includes the safe return leading to an arrest."
Blenheim Palace declined to comment on the reward.
Thames Valley Police has also released CCTV images of one of two cars thought to have been involved in the theft.
The force said the navy blue Volkswagen Golf R had cloned registration plates and "remains outstanding".
It is appealing for motorists, who were in the Woodstock area on the night of the theft, to review their dash-cam footage.
Det Insp Steven Jones said: "We have been made aware that a substantial reward being offered by the insurers for the safe return of the property subject to specific conditions."